Green Sea Turtles Get Back To Nature After Tumor Study

July 2, 1986|By Ruth Rasche of The Sentinel Staff

SEBASTIAN INLET — Five green sea turtles released into the murky water of the Indian River on Tuesday disappeared the minute they hit the water, not even coming up for air until they were out of sight.

For the past six months the endangered green turtles lived in a tank at The Living Seas at Epcot Center, where scientists studied fibrous growths afflicting the juvenile animals. Tuesday they were released at the same spot in the river where they had been captured, just south of Sebastian Inlet.

''They're used to the aquarium now, so they are probably circling in the water thinking there's a wall 200 feet away,'' said Living Seas curator Bruce Miller, who carried the turtles about 10 feet out into the river and let them go.

The turtles weighed an average of 34 pounds and ranged in age from 3 to 6 years. Although scientists still do not know what is causing their growths, the study showed that secondary effects of the soft, fleshy growths, such as abrasions and infections, are more harmful than the growths themselves.

Lew Ehrhart, a zoologist at the University of Central Florida in Orlando who led the study, said he had not seen the growths on green turtles in east Central Florida until last year.

He suspects the growths are caused by poor water quality or a water pollutant, but a more in-depth study may be done next year to see if the growths are linked to a virus.

The Indian River is a green sea turtle ''nursery,'' where juvenile turtles live for as long as six years after they hatch from nests on the beach, Ehrhart said.

Although scientists do not know exactly how the young turtles get from the ocean to the river, they do know the turtles feast on sea grasses in the river for several years until they are big enough to venture out to sea again.

Ehrhart and a group of University of Central Florida zoology graduate students count sea turtle nests along a 12-mile stretch of beach between Melbourne Beach and Sebastian Inlet each night. Since May when turtle nesting season began, 5,500 endangered loggerhead sea turtle nests have been found there, but only 13 green turtle nests have been counted.

''Green turtle nesting is down from last year, but this year could be very good for loggerheads,'' said Blair Witherington, a graduate student who keeps the counts. More than 10,000 loggerhead nests were found along the stretch last year; only 281 of the more endangered green turtle nests were counted.

The first turtle hatchlings of the season should emerge from their nests this week, Ehrhart said. The baby turtles, which average about 100 per nest, are attracted to lights along the shore. That can be deadly for them, he said. The hatchlings instinctively use the light of the moon to lead them to the ocean, but artificial beach lighting disorients them and draws them away from the water. Birds, ghost crabs or other animals devour them or the sun bakes them to death or cars crush them on State Road A1A.

Brevard County enacted an ordinance last year prohibiting artificial beach lighting after 11 p.m. during nesting season, which runs through October. Some beachfront residents ignore the law, however, Witherington said.

''Anything that deters the hatchlings from their path between the nest and the ocean is very harmful,'' he said. ''Even if they are not eaten or crushed, if they use their limited energy supply wandering around on the beach, the chances of the hatchlings making it even if they reach the water are slim.''

The scientists said the turtles face another problem: people who disrupt them while they are trying to nest.

The best way to see a turtle dig a nest and lay eggs is to walk along the edge of the surf in the dark. When a turtle track is sighted, keep all lights off and stay directly behind the turtle until it begins laying eggs. If the turtle stops digging for five minutes, it probably has begun laying, Ehrhart said. Once it begins to lay eggs, it is all right to approach the turtle with a small flashlight, he said.

''There's still plenty of time to see the turtle once she starts laying her eggs, but a lot of people don't want to wait,'' Ehrhart said. ''If people are a little bit patient, they'll see a lot more.''

If the turtle is frightened while digging its nest, it will turn and head back toward the ocean with the eggs still inside. Ehrhart said the turtles turn back during about half their attempts to come to the beach to nest. That is called a false crawl, and many times it is due to human interference, he said.